U.S. President Barack Obama, center, listens to Rijksmuseum director Wim Pijbes, seen from the back, in front of Dutch master Rembrandt's The Night Watch painting during a visit to the Rijksmuseum in Amsterdam, Netherlands, Monday, March 24, 2014. Obama will attend the two-day Nuclear Security Summit in The Hague. (AP Photo/Frank Augstein)

- Seeking to isolate Russia, President Obama and Western and Asian allies moved to indefinitely cut Moscow out of a major international coalition on Monday, including canceling an economic summit President Vladimir Putin planned to host this summer.

The moves came amid a flurry of diplomatic jockeying as the U.S. and Europe grappled for ways to punish Russia for its annexation of the Crimean Peninsula and to prevent Moscow from pressing further into Ukraine. The world powers warned that they were prepared to "intensify actions" against Russia, including ordering more severe economic sanctions, if the Kremlin escalates its incursion into Ukraine.

Separately in The Hague, in an unexpected development, Russia's foreign minister met with his Ukrainian counterpart, the highest level of contact between the two nations since Russia moved forces into Crimea nearly a month ago.

Obama huddled with the leaders of Britain, France, Germany, Italy, Canada and Japan for an emergency meeting of the Group of Seven. In a joint statement after the evening meeting, the leaders said they were suspending their participation with Russia in the Group of Eight major industrial nations until Moscow "changes course."

The G-7 leaders instead plan to meet this summer in Brussels, symbolically putting the meeting in the headquarters city of the European Union and NATO, two organizations seeking to bolster ties with Ukraine.

"Today, we reaffirm that Russia's actions will have significant consequences," the leaders' statement said. "This clear violation of international law is a serious challenge to the rule of law around the world and should be a concern for all nations."

Russia's actions have sparked one of Europe's deepest political crises in decades and drawn comparisons to the Cold War era's tensions between East and West. Obama and other Western leaders have condemned Russia's movements as a violation of international law and have ordered economic sanctions on Putin's close associates, though those punishments appear to have done little to change the Russian leaders' calculus.

In the Hague, the G-7 leaders discussed plans for increasing financial assistance to Ukraine's central government. Obama is also expected to seek support from European leaders for deeper sanctions on key sectors of the Russian economy, including its energy sector.

Obama arrived in the Netherlands Monday morning after an overnight flight from Washington. He opened his visit with a stop at Amsterdam's Rijksmuseum, where he admired Rembrandt's massive 17th-century painting "Night Watch."